Field of the Invention
The present disclosure relates to a plasma waveguide using a step part and a block part, and more particularly, to a plasma waveguide using a step part and a block part that may produce an effect of microwave matching while maximizing an effect of microwave concentration within the waveguide having a gradual reduction in height in a microwave propagation direction by using the step part simultaneously with the block part of a predetermined height provided at an inner side surface of the waveguide.
Description of the Related Art
A conventional plasma generator includes a waveguide to transmit electromagnetic waves, a 3-stub to tune a plasma impedance, and a plasma generation unit to generate a plasma, and the plasma generation unit is equipped with a discharge tube. When electromagnetic waves are transmitted to the waveguide, an electric field concentrates on the plasma generation unit of the waveguide where a plasma is generated.
Accordingly, how to concentrate an electric field effectively is an important design factor of a waveguide.
A waveguide has been developed on a trend toward gradual decrease in height from a traditional rectangular flat structure.
FIG. 1 is a full diagram illustrating a plasma reactor disclosed in Korean Patent Publication No. 10-2008-0033408 (hereinafter referred to as a related art).
Referring to FIG. 1, a plasma reactor according to the related art has a tapering shape with a height decreasing at a predetermined angle to concentrate an electric field (electromagnetic waves) being applied within a waveguide, and includes a reactor chamber at a rear end of the waveguide, in which a plasma is generated by application of the electric field. However, the related art discloses the tapered waveguide designed to minimize reflection of electromagnetic waves, but in practice, an effect of electric field concentration in the chamber where the plasma is generated, is lower than that of the rear end of the waveguide.
To solve this problem, Korean Patent No. 10-1196966 discloses a waveguide of a multi-taper structure. However, in this case, there is a problem—fine tuning of microwaves oscillated from a magnetron is difficult.
For fine tuning of microwaves, a 3-stub matching system 20 is used as shown in FIG. 1.
The 3-stub matching system has triple stubs installed at a stub interval of λg/4 when λg is a wavelength in a waveguide 18, and serves to match a characteristic impedance of the waveguide 18 with a load impedance of a low height part of the waveguide 18 to transmit maximum power to a load.
However, such a 3-stub matching system is designed for maximum power transfer to a load in applications of a waveguide of a flat structure. Also, by a structure of the 3-stub matching system penetrating through the waveguide, leaks of a weak electromagnetic field out of the waveguide and its resultant arcing occur. To solve this problem, a high-cost sealing apparatus is separately required to prevent an electromagnetic field from leaking out of the waveguide.